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DEBIAN-CVE-2026-64194

Type: advisorySource: OSV1 source record

Net::DNS versions through 1.55 for Perl allow Denial of Service via deep DNS compression pointer chains. Net::DNS::DomainName::decode follows RFC 1035 compression pointers by recursing into itself with no depth limit. It is possible to construct a name which saturates the call stack (at least with larger TCP responses), leading to a potential Denial of Service. The guard `$link < $offset` prevents forward and circular chains, but still allows arbitrarily long backward chains. The per-offset cache (`$cache`) is populated at the start of each call and short-circuits only re-traverses of the same offset - the initial descent through a fresh chain still recurses at full depth. A crafted packet can chain two-byte compression pointers so that each one points two bytes earlier than the previous, producing a chain length of `offset / 2`. For the 14-bit pointer field (max offset 16383) this gives up to ~8191 recursive frames. For a TCP DNS message the limit is the 16-bit length field (~32767 frames). Perl's default C stack handles only a few thousand frames; beyond that the process receives SIGSEGV or similar, which is a denial-of-service for any application parsing untrusted DNS data. The vulnerability is triggered by `Net::DNS::Packet->new(\$wire)` i.e. any point where the library decodes a DNS message from the network.

Announced Source revision 1
Original source ↗

DEBIAN-CVE-2026-64194

Primary source · Revision 1

Imported from structured advisory data. Source references identify upstream records or fields; verify affected versions and your deployed configuration.

Security context

Source reference: osv:DEBIAN-CVE-2026-64194

libnet-dns-perl

Source reference: /affected/0/package/name

Affected versions
1.36-1

Source reference: /affected/0/versions

Fixed versions
1.36-1+deb12u1

Source reference: /affected/0/ranges

Prerequisites
Not stated in this record

libnet-dns-perl

Source reference: /affected/1/package/name

Affected versions
1.50-1

Source reference: /affected/1/versions

1.53-1

Source reference: /affected/1/versions

1.54-1

Source reference: /affected/1/versions

1.55-1

Source reference: /affected/1/versions

Fixed versions
1.56-0+deb13u1

Source reference: /affected/1/ranges

Prerequisites
Not stated in this record

libnet-dns-perl

Source reference: /affected/2/package/name

Affected versions
1.50-1

Source reference: /affected/2/versions

1.53-1

Source reference: /affected/2/versions

1.54-1

Source reference: /affected/2/versions

1.55-1

Source reference: /affected/2/versions

Fixed versions
1.56-1

Source reference: /affected/2/ranges

Prerequisites
Not stated in this record

Structured affected-version data

Original package identities and version rules from this source.

[
  {
    "ranges": [
      {
        "type": "ECOSYSTEM",
        "events": [
          {
            "introduced": "0"
          },
          {
            "fixed": "1.36-1+deb12u1"
          }
        ]
      }
    ],
    "package": {
      "name": "libnet-dns-perl",
      "purl": "pkg:deb/debian/libnet-dns-perl?arch=source&distro=bookworm",
      "ecosystem": "Debian:12"
    },
    "versions": [
      "1.36-1"
    ],
    "database_specific": {
      "source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-64194.json"
    },
    "ecosystem_specific": {
      "urgency": "not yet assigned"
    }
  },
  {
    "ranges": [
      {
        "type": "ECOSYSTEM",
        "events": [
          {
            "introduced": "0"
          },
          {
            "fixed": "1.56-0+deb13u1"
          }
        ]
      }
    ],
    "package": {
      "name": "libnet-dns-perl",
      "purl": "pkg:deb/debian/libnet-dns-perl?arch=source&distro=trixie",
      "ecosystem": "Debian:13"
    },
    "versions": [
      "1.50-1",
      "1.53-1",
      "1.54-1",
      "1.55-1"
    ],
    "database_specific": {
      "source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-64194.json"
    },
    "ecosystem_specific": {
      "urgency": "not yet assigned"
    }
  },
  {
    "ranges": [
      {
        "type": "ECOSYSTEM",
        "events": [
          {
            "introduced": "0"
          },
          {
            "fixed": "1.56-1"
          }
        ]
      }
    ],
    "package": {
      "name": "libnet-dns-perl",
      "purl": "pkg:deb/debian/libnet-dns-perl?arch=source&distro=forky",
      "ecosystem": "Debian:14"
    },
    "versions": [
      "1.50-1",
      "1.53-1",
      "1.54-1",
      "1.55-1"
    ],
    "database_specific": {
      "source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-64194.json"
    },
    "ecosystem_specific": {
      "urgency": "not yet assigned"
    }
  }
]

Publisher severity

No explicit severity was provided.

Event
#58132 · Revision 1
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Publisher date
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